Extended Data Fig. 10: Probability of detecting a vortex as a function of the rotation frequency.

a, Cumulative distribution function obtained from the calculated sum squared differences over the whole dataset, 83 images per frequency, with each of the vortex (solid line) and vortex-free (dashed line) references (see inset images). b, With a defined threshold X (dashed-dotted lines in a) on the cumulative distribution function. Each image is assigned to a category: vortex (red empty circles), vortex-free (blue filled circles) or no classification (grey filled circles). c, Probability of detecting a vortex signal and vortex-free signal out of the selected images in b. The error bars indicate the Clopper–Pearson uncertainty associated with image classification. Top and bottom rows show the classification result for respective thresholds 0.15 and 0.30 on the cumulative distribution function, showing the independence of the signal from the threshold.